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First Co. vs WILLIS: heat pump ratings compared

Against heat pumps of the same size and type, a typical First Co. model beats 11% and a typical WILLIS model 63%. WILLIS rates higher overall.

Covers heat pumps sold new today (R-454B and R-32 refrigerant). See older R-410A models · Updated

First Co.

11%

of similar heat pumps beaten by its typical model

Well below average

21 models listed

WILLIS

63%

of similar heat pumps beaten by its typical model

Well above average

29 models listed

Rating by ratingEach bar is the share of same-size, same-type heat pumps that a typical model beats, so the two brands compare fairly even if they make different sizes.
  • Efficiency on a 5°F dayCOP at 5°FFirst Co.: Beats 34%WILLIS: Beats 44%
  • Heating power kept at 5°FCapacity at 5°F vs 47°FFirst Co.: Beats 12%WILLIS: Beats 71%
  • Winter-long heating efficiencyHSPF2First Co.: Beats 1%WILLIS: Beats 50%
  • Summer-long cooling efficiencySEER2First Co.: Beats 0%WILLIS: Beats 69%
  • Hot-day cooling efficiencyEER2First Co.: Beats 12%WILLIS: Beats 72%

Average (50%)Dashed outline: the other brand, for comparison

Want ranks, distributions per size class and cold-weather curves? Switch to Advanced

Rebate standards

Share of each brand’s models that meet the level. Programs can have other rules too.

  • CEE 2025

    First Co.
    0%
    WILLIS
    97%

  • Xcel CC

    First Co.
    0%
    WILLIS
    97%

  • CEE Advanced

    First Co.
    0%
    WILLIS
    10%

  • ENERGY STAR CC

    First Co.
    0%
    WILLIS
    86%

Top cold-climate picks, ducted 3.5–4.5 tons

Only units that keep at least 70% of their heat at 5°F, ranked on heat kept, efficiency at 5°F and seasonal efficiency (HSPF2), against units their size.

Showing Ducted, 3.5–4.5 tons (39,000–56,999 Btu/h cooling). What size is my system?

First Co.

No ducted, 3.5–4.5 tons model from First Co..

WILLIS

  1. 1FLEX60KUHR32with ducted air handler FLEXAH60KR32WILLIS4.5 tons · 53,000 Btu/h · DuctedKeeps 100% of its heat at 5°FMeets CEE 2025, CEE 2026, CEE Advanced, Xcel CC, DOE CCHP, ENERGY STAR CC
    Heat kept at 5°F
    100% (Capacity at 5°F vs 47°F)
    Top 10%
    Efficiency at 5°F
    2.10 (COP at 5°F)
    Good
    Seasonal efficiency
    10.5 (HSPF2)
    Top 10%
    85.1score / 100
  2. 2FLEX48KUHR32with ducted air handler FLEXAH48KR32WILLIS4 tons · 48,000 Btu/h · DuctedKeeps 100% of its heat at 5°FMeets CEE 2025, CEE 2026, Xcel CC, ENERGY STAR CC
    Heat kept at 5°F
    100% (Capacity at 5°F vs 47°F)
    Top 10%
    Efficiency at 5°F
    2.00 (COP at 5°F)
    Good
    Seasonal efficiency
    10.0 (HSPF2)
    Great
    78.9score / 100
  3. 3MZUHW42KR32-OWILLIS3.5 tons · 42,000 Btu/h · DuctedKeeps 86% of its heat at 5°FMeets CEE 2025, CEE 2026, Xcel CC, ENERGY STAR CC
    Heat kept at 5°F
    86% (Capacity at 5°F vs 47°F)
    Great
    Efficiency at 5°F
    1.90 (COP at 5°F)
    Below the middle
    Seasonal efficiency
    8.1 (HSPF2)
    Good
    55.7score / 100

These are certified test ratings, not a recommendation for your home. The right size comes from a load calculation by a contractor.

Next steps

The advanced view adds ranks, both brands’ models inside every size class, standout models per rating and cold-weather curves.

Open the advanced view